Add support for using Blosxom with muse-blosxom.el

Add support for using Blosxom with muse-blosxom.el

* AUTHORS: Add new authors for contrib files.

* contrib/blosxom/getstamps.pl: New file that implements fetching
  timestamps from published Muse files and placing them in a single
  timestamps file.  That file can then be used by blosxom's metadate
  plugin.  Thanks to Michael Welle for providing this file, as well as
  instructions on how to use Muse with Blosxom.

* contrib/blosxom/metadate_0_0_3: New file implementing the metadate
  plugin for blosxom.

* texi/muse.texi (Blosxom Requirements): Briefly document using Blosxom
  to serve Muse entries.

* NEWS: Add entries for these changes.